UL Flame Rating on Plastic Material Defined

All of Polycase’s products are molded in UL Recognized material. The UL flame rating is a property of the material. Therefore, not all materials have the same rating. I figured it was time I explored the differences in the ratings to better understand why the numbers vary. And by educating myself, I can share my knowledge. So let’s break it down:

UL-94 is the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing. This means that every UL-94 product has been tested to determine its flammability characteristics. This gives a preliminary indication of the product’s suitability for a particular operation. If the end unit is acceptable to be used in a particular setting can only be determined by testing on that specific unit. While UL-94 is an indicator of how the material will react, it cannot determine the exact characteristics of all components of the end unit itself.

There are two test methods: Horizontal and vertical. A rating of HB shows that the product was tested in a horizontal burn (HB) test. A flame was applied to the material and was found to burn more slowly than a specific amount of time. This time varies by material thickness.

Ratings ending in V2, V1, or V0 specify that the material was tested in the vertical position. These ratings also indicate if the material self-extinguished after the burning source was removed.

Related posts:

• Flame Rated Plastic Electronic Enclosures for Your Safety, Part Two
• Flame Rated Plastic Electronic Enclosures for Your Safety, Part One
• Protecting Your IP Protection Rating
• Plastic Enclosures and Higher Temperature Options
• Using Cable Glands to Maintain NEMA Rating in Plastic Enclosures